Shaft-cooling means for grinding-machines and the like



H. C. MITCHELL.

SHAFT COOLING MEANS FOR 4GRINDING MACHINES AND THE'LIKE.

APPLICATION FILED JUNE 15| l9l8.

Patented Sept. 7, 1920.

NAW. @d E narran 'stares Para F s I c RAYMOND o. MITCHELL, or SPRINGFIELD, OHIO, ASSIGNOR To THE WEBSTER a PERKS TOOL COMPANY, 'OE SPRINGFIELD, OHIO, A CORPORATION OE OHIO.

" SHAFT-COOLING MEANS PoR GRINDING-MACHINES AND THE LIKE.

Specification of Letters Patent.

yPatented Sept. '7, 1920.

`Application filed June 15, 1918. Serial No. 240,186.

To all whom it may concern.'

Be it known that I, RAYMOND (j. MITCH- ELL, a citizen of the United States, residing at Springfield, in the county of Clark and State of Ohio, have invented certain new and useful Improvements in Shaft- Cooling Means for Grinding-Machines and the like, of which 'the following is a speciication."

My invention relates to improvements in grinding machines, and provides a shaft mounting and shaft cooling' construction ing many troubles due to heating of the grinding wheel spindle.

Plain cylindrical grinders are commonly subject to hard usage in that they are operv ated at high speed, and are apt to be called on for continuous service and deep-cutting action, and so it is usual practice to give the grinding wheel spindle a long bearing in which the spindle must lit very snugly to attain the necessary accuracy in centervingV of the grinding wheel. Spindles, so mounted, however, are subject to deteriorationl by barking, scaling and rapid wear, and this is due vin large measure to the heat engendered in the shaft and bearings, which causes expansion that tightens the bearing and so enhances the initial heating and wearing action.' Of course the ultimate results are inaccuracy in the work, or the a1-l ternative of frequent and extensive repairs. To overcome these difliculties I propose to cool the grinding wheel spindle internally by the positive circulation therethrough of a cooling liquid, or coolant, preferably the liquid (such assoap and water) that is commonly employed to cool the contacting surfaces of the work and wheel ,and in the drawings I have illustrated an embodiment of my invention in a form .particularly available for a plain cylindrical grinder, the single View grinder mechanism and showing thewheel and'its mounting in longitudinal section.

On the bed' l0, in suitable relation to the head and tail stocks 11 and 12, by which the work is supported and rotated, the wheel stand 13 is mounted, such stand affording separated `bearing brackets 15 and 16, through which the spindle or Shaft 17 illustrating fragments. of

extendsI and 'between which the spindledriving pulley 18 is mounted. Each of these bearing brackets is suitably equipped with bushings or brasses, and lubricating means to affordv a close, well-lubricated bearing for the' spindle 17. The details of such equipment may be varied without departure from the spirit of my invention, the specific construction shown providing in connection withV each Jbearing separated bushing brasses 19 separated to admit the intermediate waste or other packing 20 to which the oil cup 21 delivers the lubricant, Y

end caps 22 suitably packed as at 23 engaging threaded ends of the brasses vto .lock them in suitably adjusted position. At the outward end of bearing 15l the cap 22 is preferably provided with a shoulder 25 and a threaded collar 26, receiving between them the races of a thrust ball bearing 27, these races also engaging a shoulder 28 and threaded collar 29 near the extremity of the spindle 17.

The spindle 17 is hollow or provided with a central cooling passage 30 from a point near its head en'd to its opposite vend where it opens as at 31 for liquid delivery, andis preferably provided with a drip bead 32, Its open end extending beyond the adjacent bearing and being within thepopen mouth of a circular receiving chamber 33, which connects directly with an outward extend? ing return pipe 34j The cooling liquid is supplied to vthe wheel-bearing end of the shaft, .preferably .within the end portion overlain by the wheel, the Shaft having an end wall 35 with an orifice 36, through which enters a stationary supply pipe 37 that is suitably connected to the supply main 38, leading from the pump 39, to the eye of which pump the return pipe 34 aforesaid is led. Thus the cooling liquid circulated byv the pump finds passage through the hollow the shaft, preferably in the same vdirection as the intended direction of rotation of the shaft so that by centrifugal action th'e cooling liquid is thrown agalnst the shaft.wall,

but, since the cooling body is whirled in the same direction as the shaft, with minimum engendering of heat due to contact of the liquid with the shaft. In the particular construction the end of pipe '37 is provided with a tapered spider 38 from the center of which projects a stem 39l carrying a spiral 40, which preferably makes several complete turns around the stem and extends close to, though not in contact with, the wall f the shaft.

of-the length of the spindle as shown, for the tendency of the shaft-rotation is to Y 4maintain the whirl, when once started.

The wheel 42 is mounted on1 the tapered end of the shaftin ordinary fashion and the customary -wheel uard 43 Surrounding the non-working peripheral portion of the wheel rigidly mounted on the frame, af-

fords suitable anchorage for brackets 44 and 45 to support portions of the piping system.

In operation it will be apparent that the positively impelledy liquid wilh flow through the shaft in whirl, keeping it cool and thus eliminating those disadvantages that arise from heating of the shaft and consequent swelling thereof and resultant tightening of the t between the shaft and its bearings,- e'fects that cumulatively tend toward undue and irregular wearing of the shaft and itsv bearings. The liquid flowing out of the remote end of ,the shaft is caught by the inclosing casing, in whatever drection it may be thrown centrifugally, and is led back to the pump for further circulation.

While Ihave herein described in detail a particular embodiment of my invention it will be apparent to 'those skilled in the art that change may be made in detail to adapt open end of the shaft, liquid impelling means connected with the supply and receptive In practice the screw thus provided need extend only a nminor portiono means, and means for causing the fluid intro' duced into the shaft-to whirl therein. v

2. Cooling means for high speed spindles, of grinding-machine-wheels and the like, comprising, in combination, thespindle, va long, snug bearing therefor, said spindle having a central bore from its load-carryinvr end and open at its remote end, a liquid cii culating pump, piping for conducting liquid from said pump to the load carrying end of the spindle and back to the pump from the opposite end, and a stationary screw `member located within the bore close to the liquid receptive end thereof, to set the liquid passing through the shaft in whirl. f

3. Cooling means'for high speed spindles, of grinding-machine-wheels and the like, comprising, in combination, the spindle, long, snug bearings for said spindle, said spindle having a central bore extending from its load carrying end and open at its remote end, a liquid circulating pump having delivery connection to a pipe entering the load carrying end of the spindlefsaid pipe supporting a screw member, free from the spindle for whirling the liquid within the spindle, anda receptive casing encircling the remote, open end of the spindle and havin@ return connection to the pump.

4. `(ooling means for high speed s indles,` vof grinding-machine-wheels and t e like,

comprising, in combination, the spindle, long, snug bearings for the said spindle, said spindle having a central bore extendmg from the load bearing end and open atthe remote end, said remote end of the spindle projecting beyond its bearing, a receptive casing enveloping the projecting end of the spindle, a liquid circulating pump 'with whichsaid casing has connection, delivery connections from said pump, includlng a plpe extending axially into the spindle bore, said .pipe bearing a screw proJe'cting axially ofi the spindle and having its leadl in the direction of rotation of the spindle, whereby7 said screw may set in whirl the liquid within the spindle in the same direction as that of the spindle rotation.

RAYMOND C.' MITCHELL. 

